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What are Speed Density tune Advantages over a regular tune?
 

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What are Speed Density tune Advantages over a regular tune?
Changes the strategy the ecu uses to control timing and fuel.

With the stock sensors in the stock locations the ECU is Using the MAF sensors mesuring air volume. IAT Sensors for intake air temp, MAP sensors for pressure, TPS, calculated load and VE to fuel the motor and correct with the wideband O2's.

The Speed density changes that to not use the MAF sensors, and move the AIT sensors down stream measuring boosted air plus all the other sensors.

Its a more crude way to tune, But because the GT-R ECU is very fast with the Wide bands, and has many other new advanced features it works well.

The main reason to do it is in high hp applications with large injectors. The computer isn't constantly fighting the fueling strategy at idle between the MAF (with a not stock signal with Larger MAF meters or Voltage translated MAF meters) and O2 readings. It will hunt at lower RPMS due to over and under fueling and the car applying correction. I have not tuned a GT-R, but this is based on my experience with other platforms. I am sure Chris Black or Jack C can chime in and get you a better answer.

You can get both to work well, depends on the tuner and the exact setup of the car.
 

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Cobb Tuning
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The biggest reason we switched to SD was a problem with the factory fueling algorithm sometimes randomly cutting the load value in the ECU in half. When this happened it would effectively cut the fuel injected in half as well. This was a HUGE problem for those cars making over 700whp, with unknown conditions that would cause it.

All else being equal, if you could design a proper intake tube and use it with maf sensor with enough range a MAF tune would be better. Once we get to the point where we are drawing SO much air into the motor, it becomes a less attractive solution because of the compromises you have to make to the MAF system to be able to get it read such a wide range of airflow.
 
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